DNA2

unta Momonari is a high school student with an unusual problem. Whenever he becomes sexually aroused by a woman, his "female allergy" kicks in, causing the poor boy to throw up. Needless to say, he is a complete failure with women, with no hope in sight. Then, one fateful day, Junta is confronted by an attractive girl in strange clothing who claims to be from the future.

The girl gives Junta her name as Karin Aoi, and tells him about how the world has become terribly overpopulated in her time, to the point where having more than one child is a crime punishable by death. At the root of the problem is a family of "Mega-Playboys": people with sexual charisma and impulses that lead each of them to have 100 children that carry the Mega-Playboy DNA, causing them and all their descendants to each have 100 children as well. All this started with a single Mega-Playboy, whom Karin has travelled back into the past to deal with.

Karin reveals to Junta that she is a "DNA Operator". Her job is to make alterations in people's DNA that will change their nature for the greater good of society. She intends to shoot the original Mega-Playboy with a DCM ("DNA Control Medicine") bullet that will alter his DNA in order to relieve him of his mega-playboy qualities, thus preventing the overpopulation problem from ever happening. She can then return to the future to receive the reward that will allow her to finally get the "nice husband, cute pet, and sweet, sweet home" she yearns for. She confirms Junta's identity, then, to his shock, promptly shoots him.

It seems that Junta, the boy who couldn't look at a naked woman without throwing up, was destined to become the original Mega-Playboy later in his life. Escaping back to her time machine, Karin arrives to a message from her boss in the future. Her hopes for a commendation on a job well done are dashed when her rather upset employer points out that the DCM bullet she was supposed to use on the Mega-Playboy was left behind in the future. By shooting Junta with the wrong DCM bullet—one which Karin planned on using to create an ideal husband—rather than eliminating the Mega-Playboy, Karin actually created him!

Now unable to return to the future until she sets things right, Karin decides to improvise by making Junta get together with the only girl who does not give him an allergic reaction: his childhood friend Ami Kurimoto (despite him not feeling any affection for her). But there is a slight problem: not even Karin herself is immune to the Mega-Playboy's charms!